Balanced-octane gasoline manufacture



1967 E. D. YORK ETAL BALANCED-OCTANE GASOLINE MANUFACTURE Filed Dec. 14,1964 w a m m w Est @Sfim k amm .3 282mm m m m E m on. m m us Qum M936 vA E m JON F W MM/ mm mm kw} l m m tmwub WM gtus v w v 1 at M m sm EEEEKE SE53 S Q Q N .QN! mmNEDmJDwmO mm 558% vw v w w a m 1 km 2255 EEEM E .3v a f mm m MN MM. vm

mum E mum m m emqo mFw u 9 T/K/ N mw R W Q m /M A f 0 5% United StatesPatent 3,305,476 BALANCED-OCTANE GASOLINE MANUFACTURE Earl D. York andHerbert G. Krane, Gary, Ind., assignors to Standard Oil Company,Chicago, M., a corporation of Indiana Filed Dec. 14, 1964, Ser. No.418,041 6 Claims. (Cl. 20879) This invention relates to an improvedprocess for manufacturing motor gasoline having improved octane ratingthroughout the boiling range thereof. More specifically, the inventionrelates to manufacture of such gasolines by catalytic reforming ofselectively blended feedstocks.

There has recently been an increase in production of automobiles havingmanual transmissions. In cars equipped with manual transmissions,particularly if the induction system alloys an appreciable degree offuel segregation (separation of light and heavy components) at lowengine speeds, the use of conventional motor gasolines results inknocking in some cylinders of the engine because of the increasedconcentration of low-octane lowboiling components. Fuel segregationfrequently occurs in induction systems under low-speedwide-open-throttle accelerations such as canoccur with cars havingmanual transmissions. Wide-open-throttle accelerations in high gear arenot possible in cars having automatic transmissions. This separation oflight and heavy fuel components is due to the very low velocity and lowturbulence of the fuel air mixture at low engine speeds. The suddenintroduction of additional fuel to the low turbulence air streamresults, for a short period of time, in the liquid fraction not beingdistributed uniformly to all cylinders.

With fuels containing high concentrations of catalytic reformate thelighter fractions consist largely of lowoctane components. Thus, whenthese low-octane components reach the cylinder knock is likely to occur.This knock, or detonation, will discontinue only when the liquid film ofheavier components on the manifold wall reaches the cylinders in anamount and at a rate sufficient to provide adequate portions of allcomponents. Thus,

the knock resulting from the inevitable fuel segregation would beeliminated if a fuel were provided having substantially balanced octaneacross its boiling range.

Our invention provides a method of producing full boiling range motorgasoline having substantially balanced octane across the boiling rangethereof by subjecting to catalytic reforming a selectively blendedreformer charge to produce a catalytic reformate having octane andboiling range characteristics such that said gasoline consistsessentially only of said reformate and sufiicient added lighthydrocarbons to impart to said gasoline the desired vapor pressure. Moreparticularly, by our invention we provide a method of producing from lowoctane naphtha a motor gasoline having balanced octane across theboiling range thereof, which gasoline consists essentially of catalyticreformate and sufficient light hydrocarbons to produce the desiredgasoline vapor pressure, which method comprises distilling said naphthato produce a low boiling fraction, and an intermediate boiling fractionand a high boiling fraction, blending portions of each of said fractionsto produce a reformate charge stream and subjecting said charge streamto catalytic reforming to produce a reformate having balanced octaneacross the boiling range thereof, and blending said reformate, Withoutfurther treatment, with light hydrocarbons to produce said gasoline.

3,305,470 Patented Feb. 21, 1967 A preferred embodiment of our inventionis a process for converting low octane naphtha to produce two motorgasolines having different research octane numbers and each of saidgasolines having substantially balanced octane across the boiling rangethereof, by distilling the naphtha into light, intermediate and heavyfractions, preparing a first catalytic reformer charge stream byblending selected portions of each of said fractions and subjecting saidfirst charge stream to catalytic reforming to produce a first motorgasoline having a balanced octane across the gasoline boiling range, andpreparing a second catalytic reformer charge stream different from saidfirst charge stream by blending selected portions of each of saidfractions and subjecting said second charge stream to catalyticreforming to produce a second motor gasoline having a research octanenumber below the research octane of said first gasoline and also havingbalanced octane across the gasoline boiling range. Preferably, thedistillation of the low octane naphtha is controlled so that the lightfraction boils within the range of about 90 to 200 F., the intermediatefraction boils within the range of 100 to 300 F., and the heavy fractionboils within the range of 200 to 400 F. For producing two balancedoctanegasolines, the first charge stream preferably consists essentially ofabout 1 to 10 volume percent of the light fraction, 60 to volume percentof the intermediate fraction, and 15 to 35 volume percent of the heavyfraction. The second charge stream for producing gasoline having a loweroctane number from the gasoline produced from the first charge streampreferably consists essentially of 10 to 30 volume percent of the lightfraction, 20 to 40 volume percent of the intermediate fraction and 40 to60 volume percent of the heavy fraction. The reforming severity employedin the first reformer, producing the higher octane gasoline, is normallythat required to produce at least about C research octane number,preferably at least about (3 research octane number. Smaller quantitiesof the light and heavy fractions are used to blend feed for the higherseverity first (premium grade) reformer than are used in blending feedfor the lower severity second reformer because the higher severityemployed in the first reformer results in greater production of lightand heavy reformate components. This selective blending of feedsimproves volatility as well as providing balanced octane across theboiling range of the reformates.

Several methods have been proposed for determining the octanedistribution throughout the boiling range of motor gasoline. One suchtest method which has proven to be satisfactory is the determination ofDelta R octane number which provides a measure of the distribution ofoctane number through gasoline boiling range. It is used in describingthe effect of fuel mal-distribution in automobiles on road octaneratings. It is defined as the research octane number (ASTM D908) of thewhole fuel minus the research octane number of a certain percentoverhead fraction of the fuel when it is distilled rapidly by aspecified procedure. A commonly used value is Delta R which is theresearch octane number of the whole fuel minus the research octanenumber of the first 75 percent distilled. This method is used by severalpetroleum companies in their research and development work. Such a testmethod has been described by: Korn, J. M., and Moss, G., TetramethylLead Reduces Low Speed Knock, SAE Summer Meeting, June 1960. Theresearch octane ratings are obtained by the usual meth- 3 ods. Delta Rratings in the range of about 3.0 to 10.0 are considered to besatisfactory. The addition of tetramethyl lead anti-knock agent inpreference to tetraethyl lead will result in lower Delta R values.

Our invention can be understood from the description of a specificembodiment in conjunction with the figure. Referring to the figure,crude oil feed from source 10 is fed via line 11 to conventional crudedistillation column 12 wherein the crude oil is separated into anoverhead fraction comprising butane, an isopentane side stream, anaphtha side stream and a bottoms fraction which is withdrawn via line15. The naphtha side stream is withdrawn from the crude distillationcolumn and passed via line 13 to a conventional hydrodesulfurizationunit 14. Desulfurized naphtha is passed from the desulfurizer 14 vialine 16 into pre-fractionator column 17. A butane and lighter gas streamis removed overhead and vented or used as fuel. Three fractions of thedesulfurized naphtha are recovered from distillation column 17 asproducts; a light fraction boiling within the range of about 90 to 200F. is withdrawn via line 18, an intermediate fraction boiling within therange of about 100 to 300 F. is withdrawn via line 19, and a heavyfraction boiling within the range of about 200 to 400 F. is withdrawnvia line 21. If desired a still higher boiling bottoms material may bewithdrawn via line 22 for use elsewhere. Two catalytic reformer feedstreams are then produced by blending selected portions of each of thethree fractions from lines 18, 19 and 21. A first catalytic reformingcharge stream for processing in a premium grade reformer 23 is preparedby introducing into the premium grade reformer charge line 24 selectedportions of each of the three fractions so that the charge blendconsists essentially of about 1 to 10 volume percent of the lightfraction from line 18, about 60 to 80 volume percent of the intermediatefraction from line 19 via line 26, and about 40 to 60 volume percent ofthe heavy fraction from line 21 via line 27. A second catalytic reformercharge blend for processing in regular grade reformer 28 is prepared byblending selected portions of each of the three fractions so that thecharge blend contains about 10 to 30 volume percent of the lightfraction from line 18 via line 29 into regular grade reformer 28 chargeline 31, about 20 to 40 volume percent of the intermediate fraction fromline 19 via line 32 into line 31 and about 40 to 60 percent of the heavyfraction from line 21 into charge line 31.

The premium grade reformer 23 is operated at a reforming severity aboveabout 90 C research octane, preferably at least about 95 C researchoctane number to produce a first reformate which is withdrawn from thereformer via line 32. A portion of each of the butane and isopentanestreams distilled from the crude oil in disitllation column 12 arepassed via lines 33 and 34, respectively, via lines 36 and 37 into line32 wherein the butane and isopentane are blended with the reformate fromreformer 23 to produce premium grade gasoline having the desired vaporpressure and substantially balanced octane throughout the boiling range.

The regular grade reformer 28 is operated at a reforming severity lowerthan the severity employed in the premium grade reformer 23. Catalyticreformate is withdrawn from regular grade reformer 28 via line 38 andblended with sufficient butane and isopentane from lines 33 and 34 toadjust the vapor pressure as desired to produce a regular grade gasolinehaving a research octane rating lower than the premium grade gasolineand having substantially balanced octane throughout the gasoline boilingrange.

EXAMPLE A hydrodesulfurized naphtha having an ASTM boiling range of 90to 330 F., was distilled into three fractions having the propertieslisted in Table I.

Selected portions of each of these three fractions were blended toproduce two reformer charge streams as shown in Table II.

TABLE II Premium Regular Composition, Vol. Percent Grade Grade ReformerReformer Light fraction 4. 7 19. 6 Intermediate l'ra 70. 3 24. 7 Heavyfract1ou 25. 0 55. 6 Gravity, AII 64. 2 63. 3

The premium reformer charge and the regular reformer charge streams weresubjected to catalytic reforming over platinum-alumina catalyst atreforming severities of 97.0 and 83.0, research octane numberrespectively. Each of the catalytic reformates produced was then blendedwith butane and isopentane to produce premium and regular gradegasolines having the desired vapor pressure and volatility and alsohaving balanced octane throughout the boiling range as indicated by theDelta R ratings. The properties of each reformate and the compositionand properties of each gasoline are shown in Table III.

TABLE III Premium Regular Reformate Properties Grade Grade ReformateRelormate Gasoline Composition Premium Regular and Properties GradeGrade Gasoline G asoline Composition, Vol. Percent:

Butane 4. 3 Isopentane 13. 5 2. 7 Reformate 86. 5 93. 0 Reid VaporPressure (RVP) 7. 5 8. (1 Delta R rating 5.0 G. 0

While our invention has been described with reference to specificembodiments and examples thereof, various alternatives will be apparentto those having skill in the art. For example, if desired, the reformercharge streams could be held in intermediate storage and reformedseparately on a blocked-out basis in a single reformer operated athigher severity to produce premium grade gasoline and at lower severityto produce regular grade gasoline. Such alternatives and variations ofour process are deemed to be within the scope of our invention.

Having thus described our invention what is claimed is 1. A method ofproducing from low octane naphtha motor gasoline having balanced octaneacross the boiling range thereof, which gasoline consists essentially ofcat alytic reformate and sutficient light hydrocarbons to produce thedesired gasoline vapor pressure, which method comprises distilling saidnaptha to produce a low boiling fraction boiling within the range ofabout 90-200 R, an intermediate boiling fraction boiling Within therange of about IUD-300 F., and a high boiling fraction boiling Withinthe range of about ZOO-400 F., blending selected portions of each ofsaid fractions to produce a reformer charge stream and subjecting saidcharge stream to catalytic reforming to produce a reformate havingbalanced octane across the boiling range thereof, and blending saidreformate without further treatment thereof, with light hydrocarbons toproduce said gasoline.

2. A method for producing from low octane naphtha motor gasoline havingsubstantially balanced octane across the boiling range thereof wherein aselected charge blend is reformed to produce a reformate suitable foruse as said motor gasoline without further treatment except for vaporpressure adjustment, which method comprises distilling said naphtha toproduce a low boiling fraction boiling Within the range of about 90-200R, an intermediate boiling fraction boiling within the range of about100-300 F., and a high boiling fraction boiling within the range ofabout ZOO-400 F., preparing a reforming charge stream blend consistingessentially of 1-20 volume percent of said low boiling fraction, 50-90volume percent of said intermediate boiling fraction, and 5-45 volumepercent of said high boiling fraction, and subjecting said reformingcharge stream blend to catalytic reforming to produce said gasoline.

3. A process for converting low octane naphtha to produce two motorgasolines having diiferent research octane numbers and each of saidgasolines having substantially balanced octane across the boiling rangethereof, by distilling said naphtha into a light fraction boiling withinthe range of about 90-200 R, an intermediate fraction boiling within therange of about 100 F.-300 F., and a heavy fraction boiling within therange of about 200- 400 F., preparing a first catalytic reformer chargestream by blending portions of each of said fractions and subjectingsaid first charge stream to catalytic reforming to produce a first motorgasoline having a balanced octane across the gasoline boiling range, andpreparing a second catalytic reformer charge stream by blending portionsof each of said fractions and subjecting said second charge stream tocatalytic reforming to produce a second motor gasoline having a researchoctane number below the research octane of said first gasoline and alsohaving balanced octane across the gasoline boiling range.

4. The process of claim 3 wherein said first catalytic reformer chargestream consists essentially of 1-10 volume percent of said lightfraction, 60-80 volume percent of said intermediate fraction, and 15-35volume percent of said heavy fraction; said second catalytic reformercharge consisting essentially of -30 volume percent of said lightfraction, 20-40 volume percent of said intermediate fraction, and 40-60volume percent of said heavy fraction.

5. A process for converting low octane naphtha to produce two motorgasolines having different research octane numbers and each of saidgasolines having substantially balanced octane across the boiling rangethereof by distilling said naphtha into a light fraction boiling withinthe range of about -200 R, an intermediate fraction boiling within therange of 100-300 F., and a heavy fraction boiling within the range ofabout 200- 400 F., preparing a first catalytic reformer charge stream byblending portions of each of said fractions and sub jecting said firstcharge stream to catalytic reforming at a severity above that requiredto produce about 90 C;,} research octane to produce a first motorgasoline having a balanced octane across the gasoline boiling range, andpreparing a second catalytic reformer charge stream by blending portionsof each of said fractions and subjecting said second charge stream tocatalytic reforming at a severity below that used in reforming saidfirst charge stream to produce a second motor gasoline having a researchoctane number below the research octane of said first gasoline andbalanced octane across the gasoline boiling range.

6. The process for converting low octane naphthas to produce a regulargrade gasoline and a premium grade gasoline, each of said gasolineshaving a substantially balanced octane throughout the gasoline boilingrange, which process comprises separating isopentane from said naphthafor blending into said gasolines; fractionating the remainder of saidnaphtha into a light fraction boiling within the range of about 90200 R,an intermediate fraction boiling within the range of about 100-300 F.,and a heavy fraction boiling within the range of about ZOO-400 F.;preparing a first catalytic reforming charge stream and a secondcatalytic reforming charge stream, said first change stream consistingessentially of 1-10 volume percent of said light fraction, 60-80 volumepercent of said intermediate fraction, and 15-35 volume percent of saidheavy fraction, and said second charge stream consisting essentially of10-30 volume percent of said light fraction, 20-40 volume percent ofsaid intermediate fraction and 40-60 volume percent of said heavyfraction; subjecting said first charge stream to catalytic reforming ata severity required to produce at least about C research octane numberto produce a first reformate, and subjecting said second charge streamto catalytic reforming at a lower severity than that employed inreforming said first charge stream to produce a second reformate;blending a first portion of said isopentane with said firstsubstantially balanced octane reformate to produce a premium gasolinehaving balanced octane throughout the gasoline boiling range, andblending a second portion of said isopentane with said secondsubstantially balanced octane reformate to produce a regular gasolinehaving balanced octane throughout the gasoline boiling range.

References Cited by the Examiner UNITED STATES PATENTS 2,890,994 6/1959Donnell et a1. 20893 3,002,917 10/ 1961 Hamilton 208-93 3,072,561 1/1963Cahn 20893 3,072,562 1/1963 Bowles 208-93 DELBERT E. GANTZ, PrimaryExaminer.

H. LEVINE, Assistant Examiner.

1. A METHOD OF PRODUCING FROM LOW OCTANE NAPHTHA MOTOR GASOLINE HAVINGBLANCED OCTANE ACROSS THE BOILING RANGE THEREOF, WHICH GASOLINE CONSISTSESSENTIALLY OF CATALYTIC REFORMATE AND SUFFICIENT LIGHT HYDROCARBONS TOPRODUCE THE DESIRED GASOLINE VAPOR PRESSURE, WHICH METHOD COMPRISESDISTILLING SAID NAPTHA TO PRODUCE A LOW BOILING FRACTION BOILING WITHINTHE RANGE OF ABOUT 90-200*F., AN INTERMEDIATE BOILING FRACTION BOILINGWITHIN THE RANGE OF ABOUT 100-300*F., AND A HIGH BOILING FRACTIONBOILING WITHIN THE RANGE OF ABOUT 200-400*F., BLENDING SELECTED PORTIONSOF EACH OF SAID FRACTIONS TO PRODUCE A REFORMER CHARGE STREAM ANDSUBJECTING SAID CHARGE STREAM TO CATALYTIC REFORMING TO PRODUCE AREFORMATE HAVING BALANCED OCTANE ACROSS THE BOILING RANGE THEREOF, ANDBLENDING SAID REFORMATE WITHOUT FURTHER TREATMENT THEREOF, WITH LIGHTHYDROCARBONS TO PRODUCE SAID GASOLINE.